Crankcase ventilation valve

ABSTRACT

A crankcase ventilation valve for an internal combustion engine has an undercut portion of the plunger body which acts as a deposit storage area for adherent deposits scraped from the flow control portion of the plunger body through its reciprocating movement in the flow control orifice. The undercut portion is located on the plunger body so that the closest end thereof enters but does not pass through the flow control orifice when the plunger is in its extreme position against its stop. In this way positive scraping of deposits into the storage area is assured without substantial effect on the valve flow curve being caused by the presence of the undercut storage area.

Lowther 123 1191;

1 1 Umted States Patent 1191 1111 McMullen 1 1 11 Oct. 23, 1973CRANKCASE VENTILATION VALVE [75] Inventor: Wesley W. McMullen, Flint,Mich. Pmfmry Exam"1er Al FawremFe sm'th 1 Assistant Exammer-MwhaelKoczo, Jr. [73] Assignee: General Motors Corporation, A r -J, L,Carpenter et a]. Detroit, Mich.

V [22] Filed: Oct. 21, 1971 57 ABSTRACT [21] PP 191,524 A crankcaseventilation valve for an'internal combustion engine has an undercutportion of the plunger 52 u.s. c1. 123/119 B, 137/480 body which acts asa deposit Storage r for adherent [51] Int. Cl. F02d 9/00 depositsscraped from the flow Control Portion of the [58] Field of Search123/119 B; 137/480 P n body/through its reciprocating movement intheflow control orifice. The undercut portion is lo- 5 References Citedcated on the plunger body so that the closest end UNITED STATES PATENTSthereof enters but does not pass through the flow control orifice whenthe plunger is in its extreme position 3,165,097 1/1965 Lowther 123/119B against its Stop- In i y positive p g of p 3,263,699 8/1966 Glvler etal. 123/119 B X 3 709 204 [1973 No one 123/1119 B 1ts 1nto the storagearea 1s assured w1thout substantlal 3'645242 2/1972 Hofiuchi." 137/48OiXeffect on the valve flow curve being caused by the 3,359,960 12/1967Pittsley.... "123/1198 Presence of the undercut Storage 3,354,898 111967 B 123 119 B UX arnes 3 Clalms, 4 Drawmg Figures CRANKCASEVENTILATION VALVE BACKGROUND OF THE INVENTION This invention relates tocrankcase ventilation flow control valves for internal combustionengines and, more particularly, to a crankcase ventilation valve forcontrolling the flow of vapors into the induction system from thecrankcase or other comparable portion of the housing of an internalcombustion engine.

It is old in the art to provide'an internal combustion engine with aso-calledcrankcase ventilation system, which includes means forrecirculating blow-by gases and other vapors from the crankcase 'orcomparable portion of an internal combustion engine to its inductionsystem. Commonly, such systems are now closed by providing means fordrawing fresh air into the crankcase from the engine air cleaner orother portion of the induction system ahead of the carburetor so as tosubstantially prevent the escape" of crankcase vapors, blow-by gases andthe like to the exterior of the engine under all operating conditions.

The majority of crankcase ventilation systems currently in use inautomotive vehicles include the provision of a flow control valve,called a crankcase ventilationvalve or PCV valve, in the conduit betweenthe engine crankcase and the engineinlet manifold or connecting portionof the induction system to control the rate of flow of blowby gases andother vapors into the engine induction system.

One type of valve which has been extensively used in commercial vehiclesin the disclosed or a modified form is shown in U.S. Pat. No. 3,359,960Pittsley, which was granted Dec. 26, 1967 to the assignee of the presentinvention. As indicated in the Pittsley patent, valves of thetypedisclosed therein include stop means which are engageable by thehead of the plunger so as to prevent a portion of the plunger adjacentthe head from entering the flow control orifice. This portion of theplunger then acts as .a dirt storage area and retains out of the flowstream some of the deposits which are scraped from the plunger flowcontrol surface.

While the operation of such valves has been highly satisfactory, ithasbeen found that under engine operating conditions which cause anexcessive rate of de posit formation 'on the crankcase ventilation valveplunger, the build-up of depositsin the dirt storage area may becomeexcessive so that it changes the flow characteristics of the valve,primarily by reducingthe flow capacity at or near the engine idleposition of the plunger. This flow reduction, if excessive, may affectengine operation by requiring'adjustments to the carburetor settings, aswell as interfere with proper ventilation of the engine crankcase. As aresult, replacement of the crankcase ventilation valve may be required.

SUMMARY OF THE INVENTION the plunger is against its stop, is' locatedwithin the flow control orifice. This point is arranged to enter but notpass through the orifice. By this construction, deposits are scraped inpositive fashion from the flow control portion of the plunger body intothe undercut deposit storage portion but this portion is prevented fromhaving any significant effect upon the flow characteristics of thevalve.

These and other features of the invention will be more apparent from thefollowing description and drawing which disclose one embodiment of flowcontrol valve formed according to the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a front elevational view of an engine having a crankcaseventilation system including a flow control DESCRIPTION OF THE PREFERREDEMBODIMENT Referring now to the drawing in detail, FIG. 1 illustrates aninternal combustion engine generally indicated by numeral 10 and havinga plurality of cylinders 12 arranged in a pair of banks angularlydisplaced with respect to one another. Cylinders: 12 are open at theirlower portions to the engine crankcase 14 which is defined by theexterior walls of the engine and by an oil pan 16. Within cylinders. 12are pistons 20 arranged for reciprocation therein and connected byconnecting rods 22 with the respective throws of crankshaft 24.

The engine includes cylinder heads 26 closing the tops of the cylindersin conventional manner and forming in cooperation with the pistonscombustion chambers 28. An induction system is providedfor introducing acombustible mixture into the combustion chamhers and includes inletports 30 formed in the cylinder heads, an 'inlet manifold 32 connectingwith the inlet ports, a carburetor 34 mounted on the inlet manifold andan inlet air cleaner 36 carried by the carburetor.

Engine 10 further includes a crankcase ventilation systemhaving an inletconduit 38 which connects the engine air cleaner 36 with the interior ofone of the en-- gine rocker covers 40. The interior of rocker cover 40.

communicates through passages, not shown, with the engine crankcase 14which, in turn, communicates through additional internal passages withthe other engine rocker cover 42.-A crankcase ventilation flow controlvalve 44 is mounted in rocker cover 42 and connects through an outletconduit 46 with the inlet manifold 32 of the engine. FIGS. 2 4 disclosein detail the construction of the crankcase ventilation flow controlvalve 44 of FIG. 1. Valve 44 is shown to include a multi -piece housing48 which is made up of a tubular body member 50 formed of sheet metaland secured by crimping at 52 to a formed outlet member 54. Member 54includes an integral outlet fitting 56 over which conduit 46 isresiliently retained. The member 54 also retains, in an enlarge'dportion adjacent fitting 56, an annular insert 58 which includes a flowcontrol orifice 60 anda longitudinally extending annular stop portion62. A backfire washer 64 is received in the end of member 50 oppositefrom the insert 58 and includes a central opening 66. The portion ofhousing 48 adjacent the backfire washer 64 is received within a rubbergrommet 68 secured within the rocker cover 42 so as to provide forreceiving crankcase vapors, including engine blowby gases, from theinterior of the engine crankcase to pass through the opening 66 andorifice 60 of the valve housing and into the engine induction system.

Within housing 48 there is reciprocably located a valve element orplunger 70. Plunger 70 includes an elongated bodyportion 72 connectingwith an enlarged head portion 74 which extends radially beyond the bodyportion into rubbing contact with the walls of the housing 48. The headportion is provided with a plurality of cutouts 76 to' permit a flow ofcrankcase vapors past the head at all times except when the head isseated against the backfire washer 64 in which condi-' tion it closesthe opening 66. The plunger body is made up of a generallytapereld fiowcontrol portion 78 which extends to the end of the plunger opposite fromhead 74 and a deep square-edged undercut deposit storage portion 80extending between the head 74 and the flow control portion 78. Flowcontrol portion 78 tapers generally from its smaller end to its largerend and is free to rub against the orifice 60 during movement therein.The smaller end of portion 78 is positioned within orifree 60 whenthe'head portion 74 is against the backfire washer 64 and the larger endis positioned within orifice 60 when the head portion 74 is against thestop 62. A coil spring 84 is provided which extends between the insertmember 58 and the underside of head portion 74 and acts to bias theplunger 70 downwardly, as shown in the drawing, in a direction to permitincreased flow through the orifice 60'. g

In operation, the vacuum created in the engine inlet manifold 32 causesa reduction in pressure in the conduit 46 and outlet fitting 56downstream of the orifice 60. This creates a flow of crankcase vaporsthrough the valve 44, the amount of which is controlled by the positionof the valve plunger 70. When the difference in pressure across theplunger is high, as when the engine is idling and inlet manifold vacuumis high, plunger 70 is urged upwardly against the force of spring 84 toa position at or near that shown in FIG. 3 of the drawing.

' In most instances the valve will be sized so that the plunger head 74is close to but not against the stop 62 when the engine is idling butwill contact the stop as shown in FIG. 3 during the highervacuurnconditions which exist during engine deceleration. In the position shownin FIG. 3, the maximum diameter of the plunger control portion 72 iswithin the orifice 60 so that a maximum restriction to flow exists andthe passage of crankcase vapors is limited accordingly.

It should be noted that the undercut deposit storage portion 80 isarranged so that one end thereof also extends within the orifice 60 whenthe plunger head is against stop 62. In this way, deposits, which maycollect upon the control surfaces of portion 72 from the crankcasevapors which flow over its surface, will be scraped off by rubbingaction of portion 72 against the inner diameter of orifice 60 anddeposited within the storage portion 80. In this way, adherent depositsare moved inwardly to the smaller diameter portion of the plunger sothat they do not block the flow of crankcase vapors when the plunger isat or near the idle position. In addition, the fact that the depositstorage area is made so as not to extend completely through the orificeat any time prevents this portion from having any significant effectupon the rate of flow through the orifice which is instead controlled bythe adjacent larger diameter end of the flow control portion 72.

The term crankcase ventilation valve is used herein as it is a commonidentifying term for such valves and is not intended to indicate anylimitation on their use which, it should be understood, may includeapplication in engines which have no crankcase or in other enginesystems.

While the-invention has been described by reference to a preferredembodiment, it should be apparent that various changes could be madewithin the scope of the inventive concepts taught and, accordingly, theinvention is intended to be limited only by the language of thefollowing claims.

I claim:

1. A flow control valve for use with an internal combustion engine tocontrol the flow of blow-by gases or the like to the engine inductionsystem, said valve comprising a housing defining a fluid flow path andhaving a flow control orifice in said flow, path,

a valve plunger within said housing, said plunger having an elongatedbody including a flow control portion of variable cross sectional arealongitudinally thereof, which is reciprocably movable within saidorifice in response to pressure differentials across the valve plungerto control fluid flow through the orifice, and

stop means in the housing and engagable by the valve plunger only at onepredetermined position thereof to stop movement of the valve plunger inone direction at said predetermined position within said orifice,

said valve plunger body having an undercut portion adjacent the flowcontrol portion, said undercut portion being positioned so that one endthereof extends into but does not pass through the orifice when saidvalve plunger is against said stop means, whereby said undercut portionforms a storage volume for adherent deposits scraped from the surface ofthe plunger body flow control portion during its movement within theorifice.

2. A crankcase ventilation valve for use with an internal combustionengine to control the flow of blow-by beyond said predetermined positionin one direction,

said deposit collection portion being formed by a substantial undercutof the elongated portion, said deposit collection portionextending fromadjacent the head to a point, on the body portion which enters but doesnot pass through the orifice when the head moves into engagement withthe stop means.

3. A crankcase ventilation valve for use with an internal combustionengine to control the flow of blow-by gases and vapors into the engineinduction system, said valve comprising a housing having a fluid flowcontrol orifice therein, a valve plunger reciprocably carried in saidhousing and having an elongated body portion and a head at one endthereof, said body portion including a sharp-edged undercut forming adeposit collection portion adjacent the head and a generally taperedflow control portion having a larger diameter, endthe end of said largerdiameter portion adjacent said undercut is within said orifice toprovide a maximum flow restriction, and

spring means in said housing and biasing said plunger in a flowincreasing direction away from said stop means.

1. A flow control valve for use with an internal combustion engine tocontrol the flow of blow-by gases or the like to the engine inductionsystem, said valve comprising a housing defining a fluid flow path andhaving a flow control orifice in said flow path, a valve plunger withinsaid housing, said plunger having an elongated body including a flowcontrol portion of variable cross sectional area longitudinally thereof,which is reciprocably movable within said orifice in response topressure differentials across the valve plunger to control fluid flowthrough the orifice, and stop means in the housing and engagable by thevalve plunger only at one predetermined position thereof to stopmovement of the valve plunger in one direction at said predeterminedposition within said orifice, said valve plunger body having an undercutportion adjacent the flow control portion, said undercut portion beingpositioned so that one end thereof extends into but does not passthrough the orifice when said valve plunger is against said stop means,whereby said undercut portion forms a storage volume for adherentdeposits scraped from the surface of the plunger body flow controlportion during its movement within the orifice.
 2. A crankcaseventilation valve for use with an internal combustion engine to controlthe flow of blow-by gases and vapors into the engine induction system,said valve comprising a housing having an orifice therein to restrictfluid flow therethrough, a valve element in said housing and having anelongated body portion and a head at one end thereof, said body portionincluding a deposit collection portion adjacent the head and a generallytapering flow control portion on the end opposite the head, and stopmeans in the housing and engagable by the head only at one predeterminedposition of the valve element to prevent movement of the valve elementbeyond said predetermined position in one direction, said depositcollection portion being formed by a substantial undercut of theelongated portion, said deposit collection portion extending fromadjacent the head to a point on the body portion which enters but doesnot pass through the orifice when the head moves into engagement withthe stop means.
 3. A crankcase ventilation valve for use with aninternal combustion engine to control the flow of blow-by gases andvapors into the engine induction system, said valve comprising a housinghaving a fluid flow control orifice therein, a valve plungerreciprocably carried in said housing and having an elongated bodyportion and a head at one end thereof, said body portion including asharp-edged undercut forming a deposit collection portion adjacent thehead and a generally tapered flow control portion having a largerdiameter, ending immediately adjacent the deposit collection portion,and a smaller diameter at its end opposite from the head, said flowcontrol portion being free to rub the edges of said orifice duringreciprocation therein, stop means in the housing and engagable by thehead in only one predetermined position of the plunger to preventmovement of the plunger in one direction beyond said predeterminedposition wherein the end of said larger diameter portion adjacent saidundercut is within said orifice to provide a maximum flow restriction,and spring means in sAid housing and biasing said plunger in a flowincreasing direction away from said stop means.